<p>Sends the given PING {@code frame}.</p> <p>PING frames may be used to test the connection integrity and to measure round-trip time.</p>
@param frame the PING frame to send @param callback the callback that gets notified when the frame has been sent
See Implementation
<p>Sends the given PING {@code frame}.</p> <p>PING frames may be used to test the connection integrity and to measure round-trip time.</p>
@param frame the PING frame to send @param callback the callback that gets notified when the frame has been sent